This invention relates to a picture quality improving technique for automatically obtaining an optimum image by capturing the characteristics of an input image in video signal handling apparatus, such as television receivers, VCRs, etc, and particularly in apparatus for digitally processing signals in a video chromatic signal processing circuit.
Digitization of video signal handling apparatus signals has made steady progress in recent years and this trend has also spread to home and private-use apparatus, such as television receivers and VCRs. This technique is used to reduce the number of necessary components and to improve reliability. Moreover, since a video chromatic signal processing circuit in particular, can be easily developed for EDTV via digitization, this technique is believed to be very promising.
In analog television, on the other hand, remarkable progress has been made and very clear images can be reproduced, as well.
However, both analog television and digital television use cathode-ray tubes (CRT), which are the most typical display devices at present. However, the dynamic range of a CRT is extremely narrow in comparison with natural light. This narrowness in the dynamic range of the display capacity imposes various limitations on the video system, such as blooming which occurs in a scene where luminance signals are bright, and the problem that black gradation cannot be accurately expressed in a dark scene.